Radiant-panel radio stimulation device

ABSTRACT

A stimulation device notably for testing radio reception devices is provided. It includes a signal generator delivering an amplitude-phase law for beam-forming purposes, transmitted in the form of a composite laser beam which illuminates a matrix of photodiodes of an emission subassembly with active modules separate from the generator, each wavelength of the beam carrying one of the signals defining the amplitude-phase law, intended for an active module. The device comprises means for measuring the orientation of the composite laser beam relative to the matrix of photodiodes of the emission subassembly and the distance traveled by the beam thereto, and correcting the phase law generated by the signal generator so as to neutralize the stray phase-shifts induced by these parameters on the signals transmitted to the emission subassembly.

FIELD OF THE INVENTION

The invention relates to the general technical field of beam-formingantennas, in particular those produced in solid state form.

The invention relates more particularly to the testing and stimulationof radio reception systems such as, for example, the radar detectors orcommunication interceptors, in particular when the latter are installedon their carrier platform.

CONTEXT OF THE INVENTION—PRIOR ART

To stimulate a radio reception system, once installed on its carrierplatform, without making any alteration thereto, one possibility is touse a stimulation device such as that described in the French patentapplication FR1700081 filed on Jan. 26, 2017.

Such a device which makes it possible to illuminate an aerial with aradio wave carrying a given phase law, comprises a plurality ofdistributed individual antennas. It also comprises an emitter moduleremote from the aerial under test and a receiver module placed in thevicinity of the radiating surface thereof. The emitter module generatesa signal resulting from the combination of a plurality of carriersignals at different carrier frequencies, each being modulated by aspecific modulation signal. It also transmits this signal to thereceiver module which comprises a plurality of individual receivers eachassociated with a radiating element. Each individual receiver performsthe demodulation of one of the modulated carrier signals received by thereceiver module, and radiates the demodulated signal to the surface ofthe aerial under test. Moreover, each individual receiver is arranged onthe receiver module such that its radiating element is located facingone of the antennas forming the radio reception system under test andthe radio signal that it emits is picked up mostly by this antenna.

This solution does however involve the use of hardware devices, theindividual receivers in particular, which have to be pressed onto theaerials of said radio reception system under test.

Consequently, without in any way being considered intrusive, such asolution has practical impacts. In particular, it limits theaccessibility to the aerials of the system being tested. Moreover, italso has limitations induced by the efficiencies of coupling of theantennas of a receiver module of the test device with those of theaerial of the system under test with which it is associated.

To stimulate a radio reception system, once installed on its carrierplatform, without making any alteration thereto, it is also possible, asis known, to make use of a conventional generation of a radio signal andof the remote emission of this signal to the radio reception system tobe tested. The distance does however demand having a certain level ofradiated power toward said radio reception system.

This constraint leads to the consideration of the solutions havingstructures similar to those of the operational emitters, radio receptionsystems for which the test is required being, in principle, suitable forreceiving the signals from such emitters.

The corresponding devices have architectures similar to radararchitectures, limited however to the emission function and, inparticular, architectures similar to those of the electron scanningradars which offer the benefit of not involving mechanical means toensure the aiming of the antenna beam in the desired direction.

These architectures are generally compact, the emitter produced in thisway being a single-piece element. Now, for the applications targeted,namely non-intrusive test applications, there is a need to separate thesubassembly generating the test signal from the subassembly radiatingthe latter, while simplifying to the maximum the structure of theradiating subassembly because the latter can be multiplied.

Consequently, the technical problem which arises, in the presence of ageneration subassembly and of a radiating subassembly that are separate,even remote, from one another, consists in finding a solution that makesit possible to transmit to the second subassembly the stimulation signalgenerated by the first subassembly, without affecting the phase lawcarried by this signal.

The test devices of the state of the art do not generally make itpossible to address this problem, inasmuch as they are generally compactdevices whose structure corresponds to the schematic diagrams of FIGS. 1and 2.

FIG. 1 presents a device structure in which the phase law is produced bycontrolled phase-shifters 11 (conventional structure) placed at theoutput of a waveform generator (GFO) 12, amplitude- andfrequency-controlled, each phase-shifter delivering a signal carrying agiven phase to an emission module 13.

FIG. 2 presents a device structure in which the phase law is produced bydirect synthesis by waveform generators 21 controlled also by anamplitude, frequency and phase control 22 (MIMO or Multiple InputMultiple Output structure).

One solution to the problem posed consists in producing a physicalseparation between the emission modules and the signal generationmodules at the output of the phase-shifted signals, just before thepower amplification, as illustrated by the dotted lines 15 of FIGS. 1and 2.

This break means physically grouping together that which produces all ofthe phase-shifted signals, whether it be a solution with phase-shiftersillustrated by FIG. 1 or a solution based on waveform generators (GFO)illustrated by FIG. 2, and in physically grouping together the poweramplification and radiation functions in a so-called emissionsubassembly and the excitation signal synthesis functions in a so-calledsignal generation subassembly.

The technical problem initially posed then therefore consists, in such acase, in finding a means that makes it possible to perform the routingof the radio signals, carrying the phase law, produced by generationmeans, signals that can reach several tens of GHz, to the amplificationand radiation means which can be remote from the former by severalmeters, even by several tens of meters.

As is known, the transmission of the electrical signals of the signalgeneration subassembly 31 to the subassembly 32 emitting the signals canbe performed by means of an offset by optical fiber 33 as in the case ofthe device illustrated by FIG. 3. Each electrical signal 311 from thewaveform generator is then carried by a light wave 312 of dedicatedwavelength.

Moreover, each light wave 312 can be transmitted separately to thecorresponding module 321 of the emitter subassembly by a dedicatedoptical fiber 33, as illustrated more particularly by FIG. 3.Alternatively, the different light waves can be multiplexed andtransmitted grouped together over one or more optical fibers.

This transmission mode, which makes it possible to ensure a transmissionwithout significant alteration of the electrical signals from the signalgeneration subassembly to the emission subassembly, nevertheless has thedrawback of maintaining a physical link, although loose, between the twosubassemblies, which can constitute a difficulty for certainapplications.

Alternatively, as is also known, the transmission of the electricalsignals from the signal generation subassembly to the subassemblyemitting these signals can be performed, without hardware support, bymeans of a radio beam or of a laser beam as explained in the Frenchpatent application FR1700081 cited previously. FIG. 4 schematicallypresents an example of test device structure, formed by twosubassemblies separate from one another in which the transmission of theelectrical signals is performed by means of an aimed composite laserbeam.

This transmission mode offers the advantage of eliminating any physicallink between the two subassemblies. On the other hand, it has thedrawback of leading to an alteration of the phase law formed by thesignals received by the emission subassembly, this alteration beingprimarily due to the direction of arrival of the received compositelaser beam relative to the emission subassembly and to the distancebetween the signal generation subassembly and the emission subassembly.

Consequently, because of the alteration of the phase law, the radio beamemitted by the emission subassembly exhibits, relative to its referencedirection which corresponds to an equi-phase distribution, a deflectionthat is different from the deflection corresponding to the desired phaselaw, carried by the electrical signals generated by the waveformgenerator.

This alteration can in certain cases be sufficient to significantlydegrade operation of the test device, such that a means has to be foundto cancel or at least significantly reduce the effects thereof.

SUMMARY OF THE INVENTION

Given the context described previously, one aim of the invention is topropose a solution that makes it possible to neutralize the effects ofthe orientation of the composite laser beam relative to the emissionsubassembly, and the distance separating the two subassemblies, on theon the orientation of the radio beam emitted by the emissionsubassembly, in other words on the phase law applied to the radiatingelements forming the emission subassembly.

To this end, the subject of the invention is a radiant panel radiostimulation device, for emitting a test signal to a reception antenna.

Said device comprises a subassembly generating excitation electricalsignals each having a phase corresponding to a desired phase law{Δφ_(n)} and at least one emission subassembly configured to amplify andradiate said electrical signals so as to emit a radio beam in adirection determined by said phase law {Δφ_(n)}.

The electrical signals are transmitted by the generator subassembly tothe emission subassembly in the form of laser waves modulated by saidsignals and forming a composite laser beam directed toward the surfaceof a set of photodetectors incorporated in the emission subassembly.

According to the invention, the electrical signal generator subassemblyand the emission subassembly are arranged facing one another such thatthe composite laser beam is directed toward the surface of the set ofphotodetectors at an incidence (α,β) relative to a reference axis andthat it travels a distance D between its point of emission M and areference point O situated on the reference axis at the surface of theset of photodetectors.

The device further comprises a correction system configured to measurethe values α, β and D and deliver a corrected phase law {Δφ′_(n)} thatis substituted for the desired phase law {Δφ_(n)}, the corrected phaselaw being defined such that the radio beam produced from the signalsgenerated by the signal generator module is oriented in the directioncorresponding to the desired phase law {Δφ_(n)}.

According to a particular provision, the corrected phase law Δφ′_(n)′ isdetermined from the calculation of the path-length differenceδ_(n)=D_(n)′−D generated, at each of the photodetectors, by the angle ofincidence of the composite laser beam on the surface of the set ofphotodetectors of the emission subassembly, Δφ′_(n)′ being defined bythe relationship:

${{\Delta\phi}_{n}^{\prime} = {{\Delta\phi}_{n} - {2\pi {\frac{f_{s}}{c} \cdot \delta_{n}}}}};$

in which D_(n)′ representing the distance between the point of emissionM of the composite laser beam and the position P_(n) of thephotodetector considered.

According to another particular provision, the photodetectors which formthe set of photodetectors of the emission subassembly are arranged in aplane (xOz) on which their positions P_(n) are registered, in terms ofpolar coordinates, by a distance d_(n)′ and an angle γ_(n)′.

The path-length difference δ_(n) is then defined, for eachphotodetector, by the following relationship:

$\delta_{n} = {{D_{n}^{\prime} - D} = {D \cdot {\left( {\sqrt{1 - {2\left( {{\cos \; \gamma_{n}^{\prime}\cos \; {\beta cos\alpha}} + {\sin \; \gamma_{n}^{\prime}\sin \; \beta}} \right)\left( \frac{d_{n}^{\prime}}{D} \right)} + \left( \frac{d_{n}^{\prime}}{D} \right)^{2}} - 1} \right).}}}$

According to another provision, the values α, β and D are determined byconsidering a plurality of non-aligned points C_(n), situated on thesurface of the set of photodetectors, and by determining the distanceD_(n) separating the point M of emission of the composite laser beamfrom each of the points C_(n) considered.

According to another provision, the values α, β and D are determined byconsidering at least three non-aligned points.

According to another provision, the points C_(n) being registered in theplane (xOz) by their distance d_(n) to the reference point O and by theangle γ_(n) between the axis linking the point C_(n) considered to thepoint O and the reference axis (Ox), D, α and β are given by thefollowing relationships:

$\begin{matrix}{D = \frac{\sqrt{\frac{d_{2}{{d_{3}\left( {D_{1}^{2} - d_{1}^{2}} \right)}\left\lbrack {{\cos \gamma_{2}{\sin \left( {\gamma_{1} - \gamma_{3}} \right)}} - {\cos \gamma_{3}{\sin \left( {\gamma_{1} - \gamma_{2}} \right)}}} \right\rbrack}}{{{d_{3}\left( {{d_{2}\cos \gamma_{2}} - {d_{1}\cos \gamma_{1}}} \right)}{\sin \left( {\gamma_{1} - \gamma_{3}} \right)}} - {{d_{2}\left( {{d_{3}\cos \gamma_{3}} - {d_{1}\cos \gamma_{1}}} \right)}{\sin \left( {\gamma_{1} - \gamma_{2}} \right)}}} +}}{\frac{d_{1}\cos \; {\gamma_{1}\left\lbrack {{{d_{2}\left( {D_{3}^{2} - d_{3}^{2}} \right)}{\sin \left( {\gamma_{1} - \gamma_{2}} \right)}} - {{d_{3}\left( {D_{2}^{2} - d_{2}^{2}} \right)}{\sin \left( {\gamma_{1} - \gamma_{2}} \right)}}} \right\rbrack}}{\begin{matrix}{{{d_{3}\left( {{d_{2}\cos \gamma_{2}} - {d_{1}\cos \gamma_{1}}} \right)}{\sin \left( {\gamma_{1} - \gamma_{3}} \right)}} -} \\{{d_{2}\left( {{d_{3}\cos \gamma_{3}} - {d_{1}\cos \gamma_{1}}} \right)}{\sin \left( {\gamma_{1} - \gamma_{2}} \right)}}\end{matrix}};}} & \; \\{\beta = {{Arcsin}\frac{{\left( {d_{1}^{2} + D^{2} - D_{1}^{2}} \right)d_{2}\cos \gamma_{2}} - {\left( {d_{2}^{2} + D^{2} - D_{2}^{2}} \right)d_{1}\cos \gamma_{1}}}{2d_{1}d_{2}D{\sin \left( {\gamma_{1} - \gamma_{2}} \right)}}\mspace{14mu} {and}}} & \; \\{\alpha = {{Arc}\; \cos {\frac{\frac{d_{1}^{2} + D^{2} - D_{1}^{2}}{2d_{1}D} - {\sin \gamma_{1}\sin \beta}}{\cos \mspace{11mu} \gamma_{1}\cos \; \beta}.}}} & \;\end{matrix}$

According to another provision, the distances D_(n) are measured bylaser rangefinding.

According to another provision, the distances D_(n) are measured byusing the composite laser beam produced by the signal generatorsubassembly.

According to another provision, the set of photodetectors consists of amatrix of photodiodes each associated with an optical filter configuredto allow the exposure of the photodiode considered only to one of themodulated laser waves forming the composite laser beam.

The technical features presented by the device according to theinvention in accordance with the various provisions listed above can, inthe context of the invention, be considered separately from one anotheror else in various combinations.

According to a particular embodiment, the device according to theinvention comprises an electrical signal generator subassembly and atleast two emission subassemblies, the aimed optic being configured todirect the composite laser beam alternately to one or other of theemission subassemblies, the phase law correction system being configuredto deliver, at each moment, the corrected phase law {Δφ_(n)′}corresponding to the subassembly to which the composite laser beam isdirected at the instant considered.

DESCRIPTION OF THE FIGURES

The features and advantages of the invention will be better appreciatedfrom the following description, a description which is based on theattached figures which present:

FIG. 1, a schematic illustration of the structure of a first type ofradiant panel radio stimulation device known from the prior art;

FIG. 2, a schematic illustration of the structure of a second type ofradiant panel radio stimulation device known from the prior art;

FIG. 3, a schematic illustration of the structure of a third type ofradiant panel radio stimulation device known from the prior art;

FIG. 4, a schematic illustration of the structure of an exemplaryembodiment of the radiant panel radio stimulation device according tothe invention;

FIGS. 5 to 7, illustrations that highlight the technical problem posedin the context of the invention and the nature of the solution providedby the invention;

FIG. 8, a schematic illustration of the structure of a particularembodiment of the device according to the invention.

It should be noted that, for the attached figures, a functional orstructural element that is the same preferably bears one and the samereference symbol.

DETAILED DESCRIPTION

FIG. 4 schematically presents, by way of nonlimiting example, thestructure of a radiant panel radio stimulation device implementing theinvention.

Such a device comprises two physically separate subassemblies:

a first subassembly 41 comprising an electrical signal generator 411producing electrical signals 412 phase-shifted relative to one anotherin accordance with a given phase law, the phase law appliedcorresponding to the direction in which it is wanted to orient theemission of the test radio signal;

a second emission subassembly 42 comprising beam-forming radiant panels,consisting of a certain number of emission modules 421 configured toeach radiate one of the electrical signals generated.

The subassembly 41 further comprises means 413, 414 and 415 that make itpossible to perform the transmission of the electrical signals 412, onan optical carrier 43 modulated by said signals, to the subassembly 42.

The subassembly 42 comprises, for its part, a set of means 422 forhandling the reception of the composite laser beam 43 and thedemodulation thereof, so as to restore the electrical signals carried bythe light wave.

The first subassembly 41 thus primarily comprises, conventionally:

a electrical signal generator 411 producing N electrical signals 412:s₀(t)=S₀ cos(ωt+Δφ₀), s₁(t)=S₁ cos(ωt+Δφ₁), . . . , s_(N-1)(t)=S_(N-1)COS(ωt+Δφ_(N-1)), the structure of said signal generator being able tobe analogous, for example, to one or other of those illustrated by FIG.1 or 2;

N laser sources of distinct wavelengths λ₀, λ₁, . . . , λ_(N-1);

N optical modulators 413, each optical modulator allowing the amplitudemodulation of a laser source of wavelength λ_(n) by an input electricalsignal S_(n) cos(ωt+Δφ_(n)); a multiplexer 415 making it possible to sumthe N modulated laser signals 414 produced, carrying the amplitude-phaselaw, and form a composite laser signal 416;

an aimed optic 417, for correctly radiating the composite laser signal416, that is to say forming a composite laser beam 43, directing it andfocusing it correctly to completely illuminate the light wave receptionmeans 422 of the emission subassembly 42. In the example of FIG. 4, themeans 422 consist of a planar matrix of photodiodes 423;

electrical energy supply and utility circuits, not represented in FIG.4.

According to the invention, the first subassembly 41 further comprises asystem for correcting the phase law applied to the signal generator 411,the system itself comprising:

a measurement module 44 making it possible to determine the quantitiesD, α and β. D represents the distance between the aimed optic 417 andthe matrix of photodiodes 422, and (α,β) represents the angularorientation of the axis of the composite laser beam 43 to a referencedirection defined by the matrix of photodiodes 422;

a correction module 45 whose role is to calculate a correctedamplitude-phase control law, intended to be applied to the signalgenerator 411, a law which is a function of the measurements of thequantities D, α and β performed by the measurement module 44.

The principle of operation of this correction device is presentedhereinbelow in the text.

The emission subassembly 42, for its part, comprises:

a matrix 422 of N photodiodes 423, each photodiode being equipped withan optical filter 424 centered on a wavelength λ_(n), allowing thiswavelength to pass and not allowing the other wavelengths λ_(n′≠n)forming the composite laser beam 43 to pass;

N power amplifiers 425, each power amplifier receiving the electricalsignal coming from a photodiode 423;

N antennas 426 disposed in a network to form a beam at the frequency

$f = \frac{\omega}{2\pi}$

from the electrical signals generated by the electrical signal generator411, each antenna 426 being powered by the output of a power amplifier425;

electrical energy supply and utility circuits, not represented in FIG.4.

FIGS. 5 to 7 illustrate the principle of operation of the correctiondevice with which the radiant panel radio stimulation device accordingto the invention is equipped.

In the context of FIGS. 5 to 7, for the purposes of simplifying theillustration, the matrix of photodiodes 423 is represented in the formof a planar structure on which the photodiodes are distributed regularlyin rows and columns.

This disposition, which makes it easier to understand the invention, isused hereinbelow in the text to describe the principle of operationthereof. It should not however be considered as a limiting feature, anyother arrangement of photodiodes making it possible to pick up all thecomponents of the composite laser beam 43 being able to be implementedin the context of the invention.

It should however be noted that, from a hardware point of view, thematrix of photodiodes 422 in principle has a certain size, due to thefact that it is necessary to space apart the photodiodes 423 for them tobe able to be illuminated adequately by the composite laser beam 43.

As FIG. 5 shows, the path D_(n)′ of the composite laser beam from thepoint M on leaving the aimed optic 417 to a given photodiode situated atthe point P_(n) of the plane (xOz) of the matrix 422 depends on areference distance D from the point M to a point O of the matrix ofphotodiodes taken as reference, the center of the matrix for example,and on the spatial angular orientation (α,β) of the reference directionOM relative to a reference direction of the matrix of photodiodes 422,the axis (Ox) for example.

Given the relative positioning of the subassemblies 41 and 42 formingthe device according to the invention, the paths D_(n)′ culminating atthe set of photodiodes have lengths which are not strictly identical.

These length differences are due, firstly, to the spatial angularorientation (α,β) of the composite laser beam 43, and, secondly, to thedistance D which may not be sufficiently great relative to the size ofthe matrix of photodiodes for its contribution to the path lengthdifferences D_(n)′ to be able to be disregarded.

These path length differences D_(n)′ are reflected by path-lengthdifferences δ_(n)=D_(n)′−D of different values for each photodiode 423.The result in a delay of the modulated laser signals which varies fromone photodiode to the other depending on the position of the photodiodeconsidered in the matrix 422.

Consequently, they induce phase-shifts Δφ_(n[deg])1,2f_([GHz])·δ_(n[mm])on the electrical signals detected by the matrix of photodiodes 422which are added ultimately for each signal to the phase corresponding tothe phase law created at the origin and emitted by the aimed optic 417.

It should be noted that a simple numeric application makes it possibleto confirm that these stray phase-shifts are not negligible.

Thus, for example, for an electrical signal, of 10 GHz frequency,carried by the laser beam 43, a path length difference of 10 mm createsa phase-shift of 120°.

Consequently, to obtain the desired phase law {Δφ_(n)}, the function ofthe correction module 45 according to the invention is to generate thephase law {Δφ_(n)} induced by the path-length differencesδ_(n)=D_(n)′−D, from the measurements of D, α and β supplied by themeasurement module 44 and to determine the phase law {Δφ_(n)′}, equal to{Δφ_(n)−Δφ_(n)}, to be generated at the generator 411.

Generally, the corrected phase law {Δφ_(n)′}, is given by therelationship:

$\begin{matrix}{{\Delta\phi}_{n}^{\prime} = {{\Delta\phi}_{n} - {2\pi {\frac{f_{s}}{c} \cdot \delta_{n}}}}} & \lbrack 001\rbrack\end{matrix}$

In the particular case illustrated by FIGS. 5 to 7, the photodiodesresponsible for detecting the composite laser beam are located placed inthe plane (xOz) on which their positions P_(n) are registered in termsof polar coordinates by the distance d_(n)′ between the point P_(n) andthe reference point O and by the angle γ_(n)′ that the segment OP_(n)forms with the reference axis (Ox), as FIG. 6 illustrates.

The path-length difference δ_(n) is therefore given, in this case, bythe following relationship:

$\begin{matrix}\begin{matrix}{\delta_{n} = {D_{n}^{\prime} - D}} \\{= {D \cdot \left( {\sqrt{1 - {2\left( {{\cos \; \gamma_{n}^{\prime}\cos \; {\beta cos\alpha}} + {\sin \; \gamma_{n}^{\prime}\sin \; \beta}} \right)\left( \frac{d_{n}^{\prime}}{D} \right)} + \left( \frac{d_{n}^{\prime}}{D} \right)^{2}} - 1} \right)}}\end{matrix} & \lbrack 002\rbrack\end{matrix}$

Consequently, for a desired phase law {Δφ_(n)}, the corrected phase law{Δφ_(n)′} to be emitted is given by the following relationship:

                                          [003]${\Delta\phi}_{n}^{\prime} = {{\Delta\phi}_{n} - {2\pi f_{s}\frac{D}{c}\left( {\sqrt{1 - {2\left( {{\cos \; \gamma_{n}^{\prime}\cos \; {\beta cos\alpha}} + {\sin \; \gamma_{n}^{\prime}\sin \; \beta}} \right)\left( \frac{d_{n}^{\prime}}{D} \right)} + \left( \frac{d_{n}^{\prime}}{D} \right)^{2}} - 1} \right)}}$

in which D, α and β represent the unknowns.

In order to have measurements of D, α and β, the measurement module 44therefore performs, for at least three non-colinear points C₁, C₂ and C₃of the plane (xOz) of the matrix of photodiodes 422, the measurements ofthe distances D₁, D₂ and D₃, separating these points from the point M ofemission of the composite laser beam 43.

Consequently, if these points C_(n) are registered in the plane (xOz) bythe distance d_(n) and the angle γ_(n), as FIG. 7 illustrates, it isdemonstrated that D, α and β are given by the following relationships:

$\begin{matrix}{D = \frac{\sqrt{\frac{d_{2}{{d_{3}\left( {D_{1}^{2} - d_{1}^{2}} \right)}\left\lbrack {{\cos \gamma_{2}{\sin \left( {\gamma_{1} - \gamma_{3}} \right)}} - {\cos \gamma_{3}{\sin \left( {\gamma_{1} - \gamma_{2}} \right)}}} \right\rbrack}}{{{d_{3}\left( {{d_{2}\cos \gamma_{2}} - {d_{1}\cos \gamma_{1}}} \right)}{\sin \left( {\gamma_{1} - \gamma_{3}} \right)}} - {{d_{2}\left( {{d_{3}\cos \gamma_{3}} - {d_{1}\cos \gamma_{1}}} \right)}{\sin \left( {\gamma_{1} - \gamma_{2}} \right)}}} +}}{\frac{d_{1}\cos \; {\gamma_{1}\left\lbrack {{{d_{2}\left( {D_{3}^{2} - d_{3}^{2}} \right)}{\sin \left( {\gamma_{1} - \gamma_{2}} \right)}} - {{d_{3}\left( {D_{2}^{2} - d_{2}^{2}} \right)}{\sin \left( {\gamma_{1} - \gamma_{2}} \right)}}} \right\rbrack}}{\begin{matrix}{{{d_{3}\left( {{d_{2}\cos \gamma_{2}} - {d_{1}\cos \gamma_{1}}} \right)}{\sin \left( {\gamma_{1} - \gamma_{3}} \right)}} -} \\{{d_{2}\left( {{d_{3}\cos \gamma_{3}} - {d_{1}\cos \gamma_{1}}} \right)}{\sin \left( {\gamma_{1} - \gamma_{2}} \right)}}\end{matrix}};}} & \lbrack 004\rbrack \\{{\beta = {{Arcsin}\frac{{\left( {d_{1}^{2} + D^{2} - D_{1}^{2}} \right)d_{2}\cos \gamma_{2}} - {\left( {d_{2}^{2} + D^{2} - D_{2}^{2}} \right)d_{1}\cos \gamma_{1}}}{2d_{1}d_{2}D{\sin \left( {\gamma_{1} - \gamma_{2}} \right)}}}}\mspace{11mu}} & \lbrack 005\rbrack \\{\alpha = {{Arc}\; \cos \frac{\frac{d_{1}^{2} + D^{2} - D_{1}^{2}}{2d_{1}D} - {\sin \gamma_{1}\sin \beta}}{\cos \mspace{11mu} \gamma_{1}\cos \; \beta}}} & \lbrack 006\rbrack\end{matrix}$

According to the invention, the distances D_(n) can thus be measured byany appropriate measurement means known from the state of the art, suchas, for example, laser rangefinding measurement means such as the laserdistance meters sold on the market and having accuracies of the order ofa millimeter.

However, in a preferred embodiment of the invention, the measurementsare performed by means of the composite laser beam 43, whichadvantageously makes it possible not to have particular equipment toproduce the measurement module 44.

From a hardware point of view, it should be noted that the points C_(n)chosen to measure the distances D_(n) can coincide with points P_(n) onwhich photodiodes are positioned. Indeed, the matrix of photodiodes isprovided at the points P_(n) with filters each allowing one of thewavelengths λ_(n) to pass.

Now, these filters can advantageously be catadioptric reflectors forwavelengths different from λ_(n′≠n) such that it is still possible touse the composite laser beam to perform the measurements of the D_(n).

It should be noted that, because the device according to the inventioncomprises two completely separate subassemblies and the transmission ofthe phase law generated by the signal generator subassembly 41 istransmitted to the emission subassembly 42 by means of a composite laserbeam aimed toward the latter using an aiming optic 417, the theoreticalstructure of the invention as illustrated by FIG. 4 can be extended tostructures implementing two or more emission subassemblies arrangedfacing the signal generator subassembly 42.

Indeed, the aimed optic 417 of the signal generator 41 can be configuredto direct a composite laser beam with an orientation from one panel tothe other sequentially, the amplitude-phase law carried by the laserbeam 43 being able to be different.

Thus, one and the same optical carrier amplitude-phase law signalgenerator 41 can control several emission subassemblies 42 to make themradiate different signals in different directions according to anappropriate sequencing, the phase laws associated with each of theemission subassemblies being the subject of a particular correction bythe correction system of the device.

FIG. 8 offers a schematic representation of a radiant panel radiostimulation device according to the invention comprising two emissionsubassemblies 42 a and 42 b.

It should be noted that, contrary to what might be thought from thefunctional schematic representation of FIG. 4, the matrix of photodiodeswith filters 422 does not, in the context of the present invention,occupy any particular position with respect to the emission modules 421.In particular, the matrix of photodiodes 422 is not necessarily placedon the face of the structure formed by the emission modules 421 oppositethe radiating face thereof. The relative positioning of the matrix ofphotodiodes and of the emission modules is more generally linked to theconstraints relating to the application considered.

1. A radiant panel radio stimulation device, for emitting a test signalto a reception antenna, said device comprising a subassembly generatingexcitation electrical signals each having a phase corresponding to adesired phase law {Δφ_(n)} and at least one emission subassemblyconfigured to amplify and radiate said electrical signals so as to emita radio beam in a direction determined by said phase law {Δφ_(n)}, theelectrical signals being transmitted by the generating subassembly tothe emission subassembly in the form of laser waves modulated by saidsignals and forming a composite laser beam directed toward the surfaceof a set of photodetectors incorporated in the emission subassembly,characterized in that, wherein the electrical signal generatorsubassembly and the emission subassembly being arranged facing oneanother so that the composite laser beam is directed toward the surfaceof the set of photodetectors with an incidence (α, β) relative to areference axis and that it travels a distance D between its point ofemission M and a reference point O situated on the reference axis at thesurface of the set of photodetectors, the device comprises a correctionsystem configured to measure the values α, β and D and deliver acorrected phase law that is substituted for the desired phase law{Δφ_(n)}, the corrected phase law being defined in such a way that theradio beam produced from the signals generated by the signal generatormodule is oriented in the direction corresponding to the desired phaselaw {Δφ_(n)}.
 2. The device as claimed in claim 1, wherein the correctedphase law {Δφ_(n)′} is determined from the calculation of thepath-length difference δ_(n)=D_(n)′−D generated, at each of thephotodetectors, by the angle of incidence of the composite laser beam onthe surface of the set of photodetectors of the emission subassembly(42), Δφ_(n)′ being defined by the relationship:${{\Delta\phi}_{n}^{\prime} = {{\Delta\phi}_{n} - {2\pi {\frac{f_{s}}{c} \cdot \delta_{n}}}}};$D_(n)′ representing the distance between the point of emission M of thecomposite laser beam and the position P_(n) of the photodetectorconsidered.
 3. The device as claimed in claim 2, wherein thephotodetectors which form the set of photodetectors of the emissionsubassembly being arranged in a plane (xOz) on which their positionsP_(n) are registered, in terms of polar coordinates, by a distanced_(n)′ and an angle γ_(n)′, the path-length difference δ_(n) is defined,for each photodetector, by the following relationship: $\begin{matrix}{\delta_{n} = {D_{n}^{\prime} - D}} \\{= {D \cdot {\left( {\sqrt{1 - {2\left( {{\cos \; \gamma_{n}^{\prime}\cos \; {\beta cos\alpha}} + {\sin \; \gamma_{n}^{\prime}\sin \; \beta}} \right)\left( \frac{d_{n}^{\prime}}{D} \right)} + \left( \frac{d_{n}^{\prime}}{D} \right)^{2}} - 1} \right).}}}\end{matrix}$
 4. The device as claimed in claim 3, wherein the values α,β and D are determined by considering a plurality of non-aligned pointsC_(n), situated on the surface of the set of photodetectors, and bydetermining the distance D_(n) separating the point M of emission of thecomposite laser beam from each of the points C_(n) considered.
 5. Thedevice as claimed in claim 4, wherein at least three non-aligned pointsare considered.
 6. The device as claimed in claim 5, wherein the pointsC_(n) being registered in the plane (xOz) by their distance d_(n) to thereference point O and by the angle γ_(n) between the axis linking thepoint C_(n) considered to the point O and the reference axis, D, α and βare given by the following relationships: $\begin{matrix}{D = \frac{\sqrt{\frac{d_{2}{{d_{3}\left( {D_{1}^{2} - d_{1}^{2}} \right)}\left\lbrack {{\cos \gamma_{2}{\sin \left( {\gamma_{1} - \gamma_{3}} \right)}} - {\cos \gamma_{3}{\sin \left( {\gamma_{1} - \gamma_{2}} \right)}}} \right\rbrack}}{{{d_{3}\left( {{d_{2}\cos \gamma_{2}} - {d_{1}\cos \gamma_{1}}} \right)}{\sin \left( {\gamma_{1} - \gamma_{3}} \right)}} - {{d_{2}\left( {{d_{3}\cos \gamma_{3}} - {d_{1}\cos \gamma_{1}}} \right)}{\sin \left( {\gamma_{1} - \gamma_{2}} \right)}}} +}}{\frac{d_{1}\cos \; {\gamma_{1}\left\lbrack {{{d_{2}\left( {D_{3}^{2} - d_{3}^{2}} \right)}{\sin \left( {\gamma_{1} - \gamma_{2}} \right)}} - {{d_{3}\left( {D_{2}^{2} - d_{2}^{2}} \right)}{\sin \left( {\gamma_{1} - \gamma_{2}} \right)}}} \right\rbrack}}{\begin{matrix}{{{d_{3}\left( {{d_{2}\cos \gamma_{2}} - {d_{1}\cos \gamma_{1}}} \right)}{\sin \left( {\gamma_{1} - \gamma_{3}} \right)}} -} \\{{d_{2}\left( {{d_{3}\cos \gamma_{3}} - {d_{1}\cos \gamma_{1}}} \right)}{\sin \left( {\gamma_{1} - \gamma_{2}} \right)}}\end{matrix}};}} \\{{\beta = {{Arcsin}\frac{{\left( {d_{1}^{2} + D^{2} - D_{1}^{2}} \right)d_{2}\cos \gamma_{2}} - {\left( {d_{2}^{2} + D^{2} - D_{2}^{2}} \right)d_{1}\cos \gamma_{1}}}{2d_{1}d_{2}D{\sin \left( {\gamma_{1} - \gamma_{2}} \right)}}}}\mspace{11mu}} \\{\alpha = {{Arc}\; \cos {\frac{\frac{d_{1}^{2} + D^{2} - D_{1}^{2}}{2d_{1}D} - {\sin \gamma_{1}\sin \beta}}{\cos \mspace{11mu} \gamma_{1}\cos \; \beta}.}}}\end{matrix}$
 7. The device as claimed in claim 4, wherein the distancesD_(n) are measured by laser rangefinding.
 8. The device as claimed inclaim 4, wherein the distances D_(n) are measured by using the compositelaser beam produced by the signal generator subassembly.
 9. The deviceas claimed in claim 1, wherein the set of photodetectors consists of amatrix of photodiodes each associated with an optical filter configuredto allow the exposure of the photodiode considered only to one of themodulated laser waves forming the composite laser beam.
 10. The deviceas claimed in claim 1, wherein it comprises an electrical signalgenerator subassembly and at least two emission subassemblies, the aimedoptic being configured to direct the composite laser beam alternately toone or other of the emission subassemblies, the phase law correctionsystem being configured to deliver, at each moment, the corrected phaselaw {Δφ_(n)′} corresponding to the subassembly to which the compositelaser beam is directed at the instant considered.